High temperature solid electrolyte electrochemical cells require intimate contact of the component materials of the cell. In an electrochemical cell described in U.S. Pat. No. 4,395,468, an air electrode is deposited on a support tube, and an electrolyte and electrode are deposited over the air electrode. In that cell, the support tube is made of a porous stabilized zirconia such as (ZrO.sub.2).sub.0.85 (CaO).sub.0.15, which has a fluorite-like crystal structure, and the air electrode material is a modified lanthanum manganite such as La.sub.0.9 Sr.sub.0.1 MnO.sub.3, which has a perovskite-like structure.
During the fabrication of the fuel cell, it is necessary to heat the materials to temperatures as high as 1300.degree. to 1400.degree. C. to form and sinter the materials into a solid mass. At these temperatures, and, to a lesser extent at the temperatures at which the fuel cell is operated, the air electrode materials can interact with the materials of the support tube. This is indicated by a discoloration of the materials of the support tube which are adjacent to the air electrode. Sometimes, cracks, delaminations, and other types of damage appear near the interface of the support tube and the air electrode. At least one of the difficulties seems to be due to the interaction that occurs between the support tube and the air electrode.